1. Field of the Invention
The present invention relates to a network system to control electronic equipment by file transfer protocol, especially image data inputting and outputting apparatuses such as digital multifunction apparatus.
2. Description of the Prior Art
The spread of networks has led to increased use of such networks by computers like work station computers and personal computers and also such equipment as network printer directly connected to the network. Communication through the network requires common standards or rules communication protocol—that are applied to the sender and the receiver. And especially, communication equipment has to be adapted to standard communication protocols. A communication protocol LPR for printing is used where the standard protocol for internet—TCP/IP—is utilized. However, LPR is originally a UNIX-type communication protocol and it is often the case that non-UNIX-type computer OS is not adapted to the protocol.
Meanwhile, the file transfer protocol (FTP) is one of the oldest communication protocols among the internet protocols. Its transfer application is provided as standard on almost all the operating systems (OS). If, therefore, FTP is made a common communication protocol between the network printer and the computer system, it can be hoped to build a printing environment applicable to any client OS.
It is so arranged that in order that a file to be received or sent by FTP, the file name is added after the, send/receive command as, for example, “RETR xxxx.” RETR is taken as command and xxxx is interpreted as file name. That is, the code says, “Retrieve a file named xxxx.” Thus, the file name is specified and the corresponding file is transferred in the FTP mode. But there is provided no command to control the operation of the printer or the like. Various methods are employed to control the operation of the printer or the like through the network.
For example, a method is disclosed in unexamined Japanese patent application No. 8-234934. In this technique, the operations required are sorted out according to the user identification (ID) logged in. In case a user wants a print, the command used in FTP is applied for control of the printer, thus bringing about a network printing setup.
Another example is described in unexamined Japanese patent application No. 9-6558. That discloses a method in which a printer status is outputted as pseudo file to a printer having a file system by LIST command of FTP.
A further example is a technique disclosed in unexamined Japanese patent application No. 7-105069. In this patent application, there is provided a scanner server. When an image data is taken from the network scanner, it sees to the client that the image data is taken from the file system.
However, the prior art image data inputting and outputting apparatus using FTP has some problems.
The method disclosed in unexamined Japanese patent application No. 8-234934 presents this problem. Operations are sorted out according to the user ID logged in as mentioned above. That makes the user management complicated.
The file system disclosed in unexamined Japanese patent application No. 9-6558 is to temporarily store inputted image data after all. It is impossible to do printing or the like after retrieving any image data accumulated in the printing apparatus, for example.
The method according to the unexamined Japanese patent application No. 7-105069 involves complicated procedures. For scanning starts after a request for retrieval is issued. That makes connection from the client difficult which times out in a specific time.
It is also pointed out that any of those techniques or methods is a solution only to a specific operation of the printer or scanner and not universally applicable to various operations as of the digital multifunction apparatus.